[Gastroenteritis outbreak associated with water consumption, possibly caused by Norwalk or Norwalk-like virus]. / Brote de gastroenteritis asociado al consumo de agua, posiblemente producido por virus tipo Norwalk o semejantes.

BACKGROUND: It is described an acute gastroenteritis outbreak of probable hydric transmission in Ontinyent (Valencia). It was declared on the 31st of January, 1992 and affected 3541 people according to the declaration done by the sanitary services who attended the patients. The clinical situation was characterized by the presence of profuse and watery diarrhoea, nausea, vomiting, abdominal pain and fever or febricula. METHODS: A preliminary study of the cases has been done, the information being treated with the classical method of descriptive epidemiology and a later study of the transversal observation type by means of a telephone inquiry. RESULTS: The results show that this outbreak affected approximately to a 30% of the population, and show the relation between consumption of water from the municipal water system and the outbreak, as well as the existence of a control population not affected for receiving a different water supply. CONCLUSION: Once rejected the bacterial origin for the results of the copro-cultivation done the analysis of the clinical and epidemiological characteristics of the outbreak, show a total agreement with the criteria described by Kaplan to characterize acute gastroenteritis outbreaks because of Norwalk-like virus.